Intro to the Spock testing framework && Co/contravariance

Join us for a new meeting of the Bucharest Java User Group. Two speakers, both of them software developers, will share with you some insights into some interesting technical topics. For more details, read on.

Intro to the Spock testing framework, a live coding session Spock is a testing framework for Groovy and Java applications. The aim of this talk is to give you a practical demonstration of Spock’s features that help you write expressive tests, and speed up the coding process. Bianca will perform a live coding session using Spock. She will be using Groovy, but fear not! If you are a little bit familiar with Java, you will see that you can easily read the code.

Speaker

Bianca Leuca Software developer @ Mozaic Labs

Covariance and contravariance in Java While merrily browsing the Internet and reading technical articles about programming, you may encounter the terms of “covariance” and “contravariance.” These sound spooky enough to make you consider closing the tab and forgetting all about it, as if it were a bad dream. It doesn’t have to be that way!

These two terms are actually abstract mathematical concepts that are (mis)used in computer science. During this talk, we’ll try to make sense of these things, together. We’ll lightly touch upon what covariance and contravariance means in a mathematical scenario (Don’t worry, we won’t be talking about functors!). Then, we’ll see how these concepts are used to describe subtyping relationships in the Java programming language. There will be code examples, of course!